I don’t know if this is about ad notifications, if it is, have you been through the Help Center topics? I’ve posted a few that might help if you haven’t. I’ve also included links to helpful topics posted by other community members.
How do I opt-in to Brave Ads?
Why don’t I see any Brave Ads after enabling them?
r/BATProject-troubleshootingfaq
Push Notification Test
Community – Windows 10 Focus Assist troubleshooting
PSA: Friendly Reminder For People Having Issues with Rewards/Ads